Omar Kelly breaks down the Dolphins' depth chart

Taimy Alvarez / Sun Sentinel

Tannehill, who produced an 88.7 passer rating, will enter his fifth season as the unquestioned starter for the Dolphins. Tannehill must yet again improve on his third-down (ranked 23rd) and red-zone (ranked 20th) throws, and get his team executing better in the fourth quarter (ranked 24th in fourth-quarter efficiency). Gase intends to help him become a better leader, and improve his pocket presence. Giving Moore a two-year deal that guarantees him $1.4 million will make him hard to cut, so don’t expect a youngster like Thomas or Doughty, Miami’s seventh-round pick, to unseat him. However, both have practice squad eligibility.

Tannehill, who produced an 88.7 passer rating, will enter his fifth season as the unquestioned starter for the Dolphins. Tannehill must yet again improve on his third-down (ranked 23rd) and red-zone (ranked 20th) throws, and get his team executing better in the fourth quarter (ranked 24th in fourth-quarter efficiency). Gase intends to help him become a better leader, and improve his pocket presence. Giving Moore a two-year deal that guarantees him $1.4 million will make him hard to cut, so don’t expect a youngster like Thomas or Doughty, Miami’s seventh-round pick, to unseat him. However, both have practice squad eligibility.

The Dolphins have an unproven stable of young tailbacks. Ajayi, who flashed at times as a rookie (187 rushing yards and one touchdown on 49 carries), might be able to handle a 200-carry workload. But there are concerns about Ayaji's durability. Williams, who averaged 3.7 yards on his 16 carries last season, will be pushed by Drake (pictured) for his role as the primary backup, and kickoff returner. Drake has a ton of ability, but has never been a team’s featured back since college. Thomas and Pead are battling to keep their NFL careers alive.

The Dolphins have an unproven stable of young tailbacks. Ajayi, who flashed at times as a rookie (187 rushing yards and one touchdown on 49 carries), might be able to handle a 200-carry workload. But there are concerns about Ayaji's durability. Williams, who averaged 3.7 yards on his 16 carries last season, will be pushed by Drake (pictured) for his role as the primary backup, and kickoff returner. Drake has a ton of ability, but has never been a team’s featured back since college. Thomas and Pead are battling to keep their NFL careers alive.